Federal regulators, in a bid to cut the number of lives lost in post-crash fires each year, ordered automakers to adopt stronger fuel tanks capable of preventing leaks during crashes at higher speeds, the Detroit News reported on December 1.Automakers will have to start meeting the new rules in the 2005-model year. The requirements will be fully phased in by 2009. Under current rules, vehicles must pass a two-part test to be certified for fire crash-worthiness. Cars and trucks are struck from behind by a flat, rigid barrier at 30 mph. They are also struck on the side at 20 mph. After the crashes, the vehicles are checked for fuel leakage. The new test will replace the flat, rigid barrier with a lighter, deformable barrier that more closely resembles a car's front end and bumper. The rear-impact test will be conducted at 50 mph. The side test will be performed at 33.5 mph. NHTSA estimates 46 percent of the cars and trucks on the road today would fail the new tests. To pass, vehicles may not spill more than a few ounces of fuel after they are struck from behind by a barrier similar to a vehicle's front end. A vehicle won't pass the new test if it spills one ounce of fuel during the crash, 5 ounces in the five minutes after the crash, or 1 ounce during any one-minute interval for 25 minutes after the crash. Vehicle fires due to fuel tank leaks are relatively rare, occurring in less than one percent of vehicles that are towed from crashes, the government said. But when they do happen, they usually are severe.